JP2009255498A - Heat-sensitive type lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-sensitive type lithographic printing plate not requiring on-press development and water development, capable of obtaining a clear print image, having sufficient printing durability, improved in greasing, and capable of reducing generation of a sticking phenomenon. <P>SOLUTION: The heat-sensitive type lithographic printing plate has an image forming layer containing a thermoplastic resin and a water-soluble polymer compound on a water-proof support body, and the image-forming layer contains at least one selected from the group comprising compounds expressed by general formulae (1)-(4) (wherein X<SB>1</SB>is -O- or -CO-O-; R<SB>1</SB>-R<SB>6</SB>are each hydrogen, alkyl or aryl; n is an integer of 1-10; R<SB>7</SB>is alkyl, aryl, alkyl carbonyl, aryl carbonyl, alkyl sulfonyl or aryl sulfonyl; R<SB>8</SB>and R<SB>9</SB>are each hydrogen, halogen, 1-4C alkyl or 1-4C alkoxy; X<SB>2</SB>is a bond or -O-; n is an integer of 1-4; R<SB>10</SB>, R<SB>10'</SB>, R<SB>11</SB>and R<SB>11'</SB>are each hydrogen, halogen, alkyl, aryl, alkoxy, alkyl carbonyl, aryl carbonyl, alkoxy carbonyl or aryloxy). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a processless printing plate, and more particularly to a heat-sensitive lithographic printing plate capable of making a plate by heat-sensitive recording, which does not require simple development by on-machine development or washing, and does not generate waste as in the ablation type.

  With the recent development of computers and peripheral devices, a planographic printing plate making method using various digital printers has been proposed. As a plate making method of such a lithographic printing plate, for example, plate making with a dry electrophotographic laser printer as described in JP-A-6-138719 and JP-A-6-250424, JP-A-9-58144 is disclosed. Making a plate using an on-demand ink jet printer using a hot-melt ink as described in Japanese Patent Publication No. JP-A 63-166590, or making a plate using a thermal printer using a thermal transfer ink ribbon described in Japanese Patent Laid-Open No. 63-166590 Things are known.

  The plate making method using the above various digital printers is different from the conventionally known plate making method of a lithographic printing plate having a silver halide emulsion layer, or the plate making method of a lithographic printing plate in which a photosensitive resin is applied to a water retaining surface. There is an advantage that a lithographic printing plate can be easily and easily made in that it is not restricted by safety light and does not require a developing treatment with a developer after image recording. The printing plates used for these plate making methods are collectively referred to as processless printing plates.

  However, all of the above processless printing plates form a printing plate by transferring a grease-sensitive (that is, lithographic printing ink deposition property) recorded image to the surface of a support provided with a water retention layer. There are the following problems.

1) Since a layer for forming an image is hydrophilic, adhesion of toner, ink, or the like is not sufficient. For example, there are problems such as insufficient transfer toner image density and whiteout transfer image.
2) The transfer image is not sufficiently fixed, and the printing durability is insufficient. In particular, there are problems such as omission of part of small point characters and small dots of a halftone dot image.
3) There is a problem that a small amount of toner is irregularly transferred to the non-image area or the thermal transfer ink ribbon is rubbed, resulting in generation of a thin background stain.

  As a method of obtaining an oleophilic image part by providing an image forming layer containing a thermoplastic resin on a support without providing a water retention layer on the support and performing thermal printing on the image forming layer, an image forming layer is used. In addition, a method of obtaining an oleophilic image portion by directly drawing with a thermal head or the like without using a thermal transfer ribbon or the like, or a method of obtaining an oleophilic image portion by performing heat drawing with an infrared laser or the like is known.

  As a direct thermal lithographic printing plate used in a plate making method for directly performing heat drawing with a thermal head or the like without using a thermal transfer ribbon or the like, for example, Japanese Patent Laid-Open No. 58-199153 (Patent Document 1) or Japanese Patent Laid-Open No. 59-174395. A direct heat-sensitive lithographic printing plate having an image forming layer containing a water-soluble polymer compound and a heat-meltable substance described in Japanese Patent Publication (Patent Document 2) is known. On the other hand, as a heat-sensitive lithographic printing plate used in a method for obtaining an oleophilic image portion by drawing by heating with an infrared laser or the like, for example, Japanese Patent Application Laid-Open No. 2000-190649 (Patent Document 3) and Japanese Patent Application Laid-Open No. 2000-301847. There is known a heat-sensitive lithographic printing plate having an image forming layer containing heat-meltable particles or a thermoplastic polymer described in (Patent Document 4) and the like.

  However, such heat-sensitive lithographic printing plates and direct heat-sensitive lithographic printing plates generally do not have a sufficient difference in hydrophilicity / lipophilicity between the non-image area and the image area. The problem was that the property was insufficient or the soil was easily soiled. Further, since the direct thermal lithographic printing plate described in Patent Document 1, Patent Document 2 and the like is directly heated and drawn by a thermal head or the like, the hot melt is further cooled at the time of heating and drawing in addition to the above problems. There has been a problem that a so-called sticking phenomenon, which is fixed to the thermal head, easily occurs.

  As a heat-sensitive lithographic printing plate capable of obtaining a high image density, for example, an image forming layer having an inorganic pigment, a thermoplastic resin and a heat-meltable substance as described in JP-A-63-64747 (Patent Document 5) Thermal lithographic printing plates having the following are known: In addition, the thermosensitive lithographic printing plates described in Patent Document 3 and Patent Document 4 described above identify hot-melt fine particles that exhibit lipophilicity in order to improve the balance between the lipophilicity of the image area and the hydrophilicity of the non-image area. A method of coating with a substance having a thermal conductivity of 2 and a device for hydrophobizing hydrophilic groups of a hydrophilic polymer using a chelate reaction by heat are disclosed. However, in both cases, it is difficult to control the reaction, and the difference in hydrophilicity / lipophilicity between the non-image area and the image area is not sufficient, so that it is difficult to obtain a clear printed image, the printing durability is insufficient, or the background is stained. There was a problem that it was easy.

On the other hand, in JP-A-6-270572 (Patent Document 6) and JP-A-7-25175 (Patent Document 7), a sticking phenomenon occurs by introducing a thermoplastic substance that generates a hydroxyl group by thermal decomposition. A direct heat-sensitive lithographic printing plate with reduced is described. However, in either case, the difference between the lipophilicity of the image area and the hydrophilicity of the non-image area was not sufficient.
JP 58-199153 A JP 59-174395 A JP 2000-190649 A Japanese Patent Laid-Open No. 2000-301846 JP-A 63-64747 JP-A-6-270572 Japanese Patent Laid-Open No. 7-25175

  An object of the present invention is a heat-sensitive lithographic printing plate that does not require on-press development or water development, a heat-sensitive lithographic printing plate that provides a clear printed image, has sufficient printing durability, and has improved background stains. The purpose is to provide a lithographic printing plate. It is another object of the present invention to provide a direct heat-sensitive lithographic printing plate in which the occurrence of sticking phenomenon is reduced.

The above problems have been solved by the following means.
(1) In a heat-sensitive lithographic printing plate having an image forming layer containing a thermoplastic resin and a water-soluble polymer compound on a water-resistant support, the image forming layer is represented by the following general formulas (1) to (4). A heat-sensitive lithographic printing plate comprising at least one selected from the above compounds.

In the general formula (1), X ₁ represents —O— or —CO—O—, and R _{1 to} R ₆ represent a hydrogen atom, an alkyl group, and an aryl group, respectively. n represents an integer from 1 to 10.

In the general formula (2), R ₇ represents an alkyl group, an aryl group, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, or an arylsulfonyl group.

In the general formula (3), R ₈ and R ₉ represent a hydrogen atom, a halogen atom, an alkyl group having 4 or less carbon atoms, or an alkoxy group. X ₂ represents a simple bond or —O—, and n represents an integer of 1 to 4.

In the general formula (4), R ₁₀ , R _{10 ′} , R ₁₁ and R _{11 ′} are a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, An aryloxy group is shown.

(2) The heat-sensitive lithographic printing plate as described in (1) above, wherein the image forming layer contains substantially no inorganic pigment.
(3) The heat-sensitive lithographic printing plate as described in (1) or (2) above, wherein the thermoplastic resin is a self-crosslinking type synthetic rubber latex.
(4) The heat-sensitive lithographic printing plate as described in any one of (1) to (3) above, wherein the heat-sensitive lithographic printing plate is a direct heat-sensitive lithographic printing plate.

  According to the present invention, a heat-sensitive lithographic printing plate that does not require on-press development or water development, a clear lithographic printing plate is obtained, has sufficient printing durability, and has improved background contamination. A print version can be provided. Furthermore, it is possible to provide a direct heat-sensitive lithographic printing plate in which the occurrence of sticking phenomenon is reduced.

  The lithographic printing plate of the present invention contains a thermoplastic resin and a water-soluble polymer compound as an image forming layer, and the image forming layer is selected from the compounds represented by the general formulas (1) to (4). By containing at least one kind, when the surface of the image forming layer is applied with heat, the melting start temperature of the thermoplastic resin is lowered, and an image part having excellent lipophilicity on the plate surface is obtained with less energy, and a clear printed image is obtained. A heat-sensitive lithographic printing plate having sufficient printing durability can be obtained. The compounds represented by the general formulas (1) to (4) of the present invention are extremely effective for imparting sufficient printing durability, while having a very specific effect of not reducing the hydrophilicity of the non-image area. The resulting compound. As a result, a clear printed image can be obtained, and a heat-sensitive lithographic printing plate having sufficient printing durability and improved background stain can be provided. In addition, in the direct heat-sensitive lithographic printing plate used in the plate making method for performing direct heat drawing with a thermal head or the like, an extremely excellent effect of further improving the sticking phenomenon in addition to the above effect can be obtained.

  The compound represented by the general formula (1) will be described below.

In the above formula, X ₁ represents —O— or —CO—O—, and R _{1 to} R ₆ represent a hydrogen atom, an alkyl group, and an aryl group, respectively. n represents an integer from 1 to 10. The substituents R _{1 to} R ₃ and R _{4 to} R ₆ may be bonded to each other to form an aromatic ring.

Among the compounds represented by the general formula (1), compounds in which X ₁ is —O— are preferable, and R ₁ and R ₆ are particularly a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R _{2 to} R _5. A compound in which is a hydrogen atom and n is an integer of 1 to 4 is particularly preferably used. A preferable compounding amount is 30 to 130% by mass, more preferably 50 to 100% by mass with respect to the thermoplastic resin. This compound may be used alone or in combination with other heat-meltable substances.

Examples of the compound represented by the general formula (1) include the following compounds, but the present invention is not limited thereto.
(1) 1- (1-naphthoxy) -2-phenoxyethane (2) 1- (2-naphthoxy) -4-phenoxybutane (3) 1- (2-isopropylphenoxy) -2- (2-naphthoxy) ethane (4) 1- (4-Methylphenoxy) -3- (2-naphthoxy) propane (5) 1- (2-methylphenoxy) -2- (2-naphthoxy) ethane (6) 1- (3-methylphenoxy ) -2- (2-naphthoxy) ethane (7) 1- (2-naphthoxy) -2-phenoxyethane (8) 1- (2-naphthoxy) -6-phenoxyhexane (9) 1-phenoxy-2- ( 2-phenylphenoxy) ethane (10) 1- (2-methylphenoxy) -2- (4-phenylphenoxy) ethane (11) 1,4-diphenoxybutane (12) 1,4-bis (4-methylphenyl) Noxy) butane (13) 1,2-di (3,4-dimethylphenoxy) ethane (14) 1-phenoxy-3- (4-phenylphenoxy) propane (15) 1- (4-tert-butylphenoxy)- 2-phenoxyethane (16) 1,2-diphenoxyethane (17) 1- (4-methylphenoxy) -2-phenoxyethane (18) 1- (2,3-dimethylphenoxy) -2-phenoxyethane (19 ) 1- (3,4-dimethylphenoxy) -2-phenoxyethane (20) 1- (4-ethylphenoxy) -2-phenoxyethane (21) 1- (4-isopropylphenoxy) -2-phenoxyethane (22 ) 1,2-bis (2-methylphenoxy) ethane (23) 1- (2-methylphenoxy) -2- (4-methylphenoxy) ethane (24) -(4-tert-Butylphenoxy) -2- (2-methylphenoxy) ethane (25) 1,2-bis (3-methylphenoxy) ethane (26) 1- (3-methylphenoxy) -2- (4 -Methylphenoxy) ethane (27) 1- (4-ethylphenoxy) -2- (3-methylphenoxy) ethane (28) 1,2-bis (4-methylphenoxy) ethane (29) 1- (2,3 -Dimethylphenoxy) -2- (4-methylphenoxy) ethane (30) 1- (2,5-dimethylphenoxy) -2- (4-methylphenoxy) ethane (31) phenoxyacetic acid-2-naphthyl (32) 2 Naphthoxyacetic acid-4-methylphenyl (33) 2-naphthoxyacetic acid-3-methylphenyl

  Next, the compound represented by the general formula (2) will be described.

In the above formula, R ₇ represents an alkyl group, an aryl group, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, or an arylsulfonyl group. The naphthalene ring in the formula may further have a substituent, and examples of preferable substituents include an alkyl group, an aryl group, a halogen group, a hydroxy group, an alkoxy group, an aryloxy group, and an alkyloxycarbonyl group. , Alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, sulfamoyl group and the like.

Among the substituents represented by R ₇ in the general formula (2), an alkyl group having 4 to 20 carbon atoms, an aryl group having 4 to 24 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, and a carbon number having 7 to 20 carbon atoms. An arylcarbonyl group is more preferred. In the general formula (2), among the substituents that the naphthalene ring may further have, a halogen group, an alkyl group having 1 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 20 carbon atoms, or a 7 to 20 carbon atom. An aryloxycarbonyl group and a carbamoyl group having 2 to 25 carbon atoms are more preferable. A preferable blending amount is 30 to 130% by mass, more preferably 50 to 100% by mass with respect to the thermoplastic resin. This compound may be used alone or in combination with other heat-meltable substances.

Examples of the compound represented by the general formula (2) include the following compounds, but the present invention is not limited thereto.
(1) 1-benzyloxynaphthalene (2) 2-benzyloxynaphthalene (3) 2-p-chlorobenzyloxynaphthalene (4) 2-p-isopropylbenzyloxynaphthalene (5) 2-dodecyloxynaphthalene (6) 2 Decanoyloxynaphthalene (7) 2-Myristoyloxynaphthalene (8) 2-p-tert-butylbenzoyloxynaphthalene (9) 2-Benzoyloxynaphthalene (10) 2-Benzyloxy-3-N- (3-dodecyl Oxypropyl) carbamoylnaphthalene (11) 2-benzyloxy-3-N-octylcarbamoylnaphthalene (12) 2-benzyloxy-3-dodecyloxycarbonylnaphthalene (13) 2-benzyloxy-3-p-tert-butylphenoxy Carbonyl naphthalene

  Next, the compound represented by the general formula (3) will be described.

In the above formula, R ₈ and R ₉ represent a hydrogen atom, a halogen group, an alkyl group having 4 or less carbon atoms, or an alkoxy group. X ₂ represents a simple bond or —O—, and n represents an integer of 1 to 4.

Examples of the compound represented by the general formula (3) include the following compounds, but the present invention is not limited thereto.
(1) Dibenzyl oxalate (2) Di (p-methylbenzyl) oxalate
(3) Oxalate di (p-chlorobenzyl)
(4) Oxalic acid di (m-methylbenzyl)
(5) Dioxalate (p-ethylbenzyl)
(6) Dioxalate (p-methoxybenzyl)
(7) Bisoxalate (2-phenoxyethyl)
(8) Bis oxalate (2-o-chlorophenoxyethyl)
(9) Bis oxalate (2-p-chlorophenoxyethyl)
(10) Bis-oxalate (2-p-ethylphenoxyethyl)
(11) Bisoxalate (2-m-methoxyphenoxyethyl)
(12) Bisoxalate (2-p-methoxyphenoxyethyl)
(13) Bis-oxalate (4-phenoxybutyl)

  Preferred examples of these exemplary compounds include dibenzyl oxalate, di (p-methylbenzyl) oxalate, di (p-chlorobenzyl) oxalate, di (m-methylbenzyl) oxalate, and dioxalate. (P-ethylbenzyl) and di (p-methoxybenzyl) oxalate. A preferable compounding amount is 30 to 130% by mass, more preferably 50 to 100% by mass with respect to the thermoplastic resin. This compound may be used alone or in combination with other heat-meltable substances.

  The compound represented by the general formula (4) will be described below.

In the above formula, R ₁₀ , R _{10 ′} , R ₁₁ and R _{11 ′} represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group or an aryloxy group. .

Examples of the compound represented by the general formula (4) include the following compounds, but the present invention is not limited thereto.
(1) 1,2-diphenoxymethylbenzene (2) 1,3-diphenoxymethylbenzene (3) 1,4-di (2-methylphenoxymethyl) benzene (4) 1,4-di (3-methyl Phenoxymethyl) benzene (5) 1,3-di (4-methylphenoxymethyl) benzene (6) 1,3-di (2,4-dimethylphenoxymethyl) benzene (7) 1,3-di (2,6 -Dimethylphenoxymethyl) benzene (8) 1,4-di (2-chlorophenoxymethyl) benzene (9) 1,2-di (4-chlorophenoxymethyl) benzene (10) 1,3-di (4-chloro Phenoxymethyl) benzene (11) 1,2-di (4-octylphenoxymethyl) benzene (12) 1,3-di (4-octylphenoxymethyl) benzene (13) 1,3-di (4- Isopropyl phenyl phenoxymethyl) benzene (14) 1,4-di (4-isopropylphenyl phenoxymethyl) benzene

  Among these exemplified compounds, preferred specific examples include 1,2-diphenoxymethylbenzene, 1,4-di (2-methylphenoxymethyl) benzene, 1,4-di (3-methylphenoxymethyl) benzene, 1,4-di (2-chlorophenoxymethyl) benzene is mentioned. A preferable compounding amount is 30 to 130% by mass, more preferably 50 to 100% by mass with respect to the thermoplastic resin. This compound may be used alone or in combination with other heat-meltable substances.

  Among the compounds represented by the general formulas (1) to (4), the compounds represented by the general formulas (1), (2), and (4) are preferable in that excellent printing durability can be obtained. The compounds represented by (1) and (2) are preferred, and the most preferred compound is the compound represented by the general formula (1). These may be used alone or in combination.

  The compounds represented by the above general formulas (1) to (4) are substances that are solid at room temperature, but are preferably used after being subjected to fine dispersion treatment in order to increase the reactivity with heat. As a fine dispersion treatment method, a bead mill such as a roll mill, a colloid mill, a ball mill, an attritor, a sand mill, or the like, which is a wet dispersion method generally used at the time of coating production, can be used. In the bead mill, ceramic beads such as zirconia, titania and alumina, metal beads such as chrome and steel, and glass beads can be used. The dispersed particle diameter is preferably from 0.1 to 1.2 μm in median diameter, particularly preferably from 0.3 to 0.8 μm. The median diameter is the particle diameter (cumulative average diameter) at which the cumulative curve becomes 50% when the total curve of one population of particles is 100%, and the particle size distribution is evaluated. As one of the parameters to be measured, it can be measured using a laser diffraction / scattering particle size distribution measuring apparatus LA920 (manufactured by Horiba, Ltd.) or the like.

  As a heat-meltable substance that can be used in combination with the compounds represented by the above general formulas (1) to (4), an organic compound having a melting point of 50 to 150 ° C. is preferable, for example, carnauba wax, microcrystalline wax, paraffin wax, Waxes such as polyethylene wax, fatty acids such as lauric acid, stearic acid, oleic acid, palmitic acid, behenic acid and montanic acid, and esters and amides thereof can be used. If the melting point is less than 50 ° C., it may melt during the production process and cause grounding of the printed matter. On the other hand, when it exceeds 150 ° C., it is difficult to melt by applying heat from a thermal head or the like, and the lipophilicity may be poor. Moreover, when using these heat-meltable substances and the compounds represented by the general formulas (1) to (4) in combination, the amount of the heat-meltable substance added is the amount of the compounds represented by the general formulas (1) to (4). It is preferable that it is 30 mass% or less, More preferably, it is 15 mass% or less.

  The image forming layer of the heat-sensitive lithographic printing plate of the present invention contains a thermoplastic resin. Such a thermoplastic resin is a solid organic polymer compound made of a chain polymer and exhibiting plasticity by heating, and refers to an aqueous dispersion of the organic polymer compound. Typical examples are synthetic rubber latex including modified products such as styrene butadiene copolymer, acrylonitrile butadiene copolymer, methyl methacrylate butadiene copolymer, styrene acrylonitrile butadiene copolymer, styrene methyl methacrylate butadiene copolymer. Styrene maleic anhydride copolymer, methyl vinyl ether maleic anhydride copolymer, polyacrylic acid copolymer, polystyrene, styrene / acrylic acid ester copolymer, polyacrylic acid ester, polymethacrylic acid ester, acrylic acid ester / Aqueous dispersions such as acrylic ester copolymers and low melting point polyamide resins can also be used. These thermoplastic resins can be used alone or in combination of two or more. Synthetic rubber latex is preferably used as the thermoplastic resin because of its affinity with the printing ink vehicle (binder component). Such synthetic rubber latex is preferably of a type that self-crosslinks when heated from the viewpoint of printing durability. The self-crosslinking type can be three-dimensionally networked by heat without the presence of a crosslinking agent. When producing such a synthetic rubber latex, as a copolymerization component, a carboxyl group, a hydroxyl group, a methylolamide group, an epoxy It can be obtained by the presence of a reactive functional group such as a group, a carbonyl group or an amino group. Further, when the heat-sensitive lithographic printing plate of the present invention is a direct heat-sensitive lithographic printing plate, the image forming layer is preferably the outermost layer, and is a layer having an oleophilic image portion in printing. At the same time, it acts as a layer having a hydrophilic non-image portion. Accordingly, the reactive functional group of the self-crosslinking type synthetic rubber latex is preferably a carboxyl group, a hydroxyl group, and an amino group, and particularly preferably a synthetic rubber latex having a carboxyl group as a reactive functional group. As a result, the image part is self-cross-linked to obtain good printing durability, and at the same time, the non-image part that is not heated is preferable because it provides excellent water retention. A particularly preferred synthetic rubber latex is a carboxy-modified styrene butadiene copolymer. A preferable blending amount of the thermoplastic resin is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass with respect to the total solid content of the image forming layer. Moreover, in order to make it easy to express the effect of melting and fusing by heat, it is preferable to use a thermoplastic resin having a glass transition temperature of 50 to 150 ° C, more preferably 55 to 120 ° C. If the glass transition temperature is less than 50 ° C., a phase change occurs in a liquid state during the production process, and oleophilicity appears in the non-image area, which may cause printing stains. When the temperature exceeds 150 ° C., the polymer is hardly melted by heat, and it may be difficult to form a strong image with a relatively small output laser or a small thermal printer.

  The image forming layer of the heat-sensitive lithographic printing plate of the present invention contains a water-soluble polymer compound. Examples of such water-soluble polymer compounds include polyvinyl alcohol, carboxy-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, starch and derivatives thereof, gelatin, casein, and sodium alginate. And polyvinylpyrrolidone, styrene / maleic acid copolymer salt, styrene / acrylic acid copolymer salt, and the like. These water-soluble polymer compounds may be used alone or in combination of two or more, and gelatin, polyvinyl alcohol and modified products thereof, which are particularly rich in film formation, are preferably selected for maintaining the hydrophilicity of the non-image area. The blending amount is preferably 0.5 to 30% by mass, more preferably 3 to 25% by mass with respect to the total solid content of the image forming layer.

  In order to improve the water resistance and mechanical strength of the non-image area, the image forming layer preferably contains a curing agent (waterproofing agent) according to the type of the water-soluble polymer compound. As the curing agent, melamine resin, epoxy resin, polyisocyanate compound, aldehyde compound, silane compound, chromium alum, divinyl sulfone and the like that can impart water resistance by promoting the crosslinking of the resin can be used. As the hardener, divinyl sulfone is preferably used in the case of gelatin, and glyoxal is preferably used in the case of polyvinyl alcohol. In addition, in order to obtain necessary water resistance and mechanical strength, and further avoid characteristic fluctuations over time when stored, the blending amount of the curing agent is 1 to 30 mass with respect to the solid content of the water-soluble polymer compound. % Is preferable, and 2 to 15% by mass is more preferable.

  The image-forming layer of the heat-sensitive lithographic printing plate of the present invention is obtained by further adding a photothermal conversion substance in addition to the compounds represented by the general formulas (1) to (4), the thermoplastic resin, and the water-soluble polymer compound. In addition to the thermal head, writing with active light such as an infrared laser becomes possible. From this viewpoint, the image forming layer of the heat-sensitive lithographic printing plate of the present invention preferably contains a photothermal conversion substance. As the photothermal conversion substance that can be used in the present invention, a material that efficiently absorbs light and converts it into heat is preferable. Depending on the light source used, for example, when a semiconductor laser that emits near infrared light is used as the light source. Is preferably a near-infrared light absorber having an absorption band in the near-infrared, for example, carbon black, cyanine dyes, polymethine dyes, azurenium dyes, squalium dyes, thiopyrylium dyes, naphthoquinone dyes, anthraquinone dyes Organic compounds such as dyes, metal compounds such as phthalocyanine, azo, and thioamide organometallic complexes, iron powder, graphite powder, iron oxide powder, lead oxide, silver oxide, chromium oxide, iron sulfide, chromium sulfide, etc. Is mentioned.

  The heat-sensitive lithographic printing plate of the present invention is a developer or color developing agent (electron-donating property) such as a phenol derivative or an aromatic carboxylic acid derivative used for general heat-sensitive recording paper or pressure-sensitive recording paper for ensuring visibility. Dye precursor).

  Specific examples of the developer that can be used in the present invention include 4-cumylphenol, hydroquinone monobenzyl ether, 4,4′-isopropylidenediphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4, 4'-dihydroxydiphenyl-2,2-butane, 4,4'-dihydroxydiphenylmethane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 2,2-bis (4-hydroxyphenyl) heptane, Bis (4-hydroxyphenylthioethoxy) methane, 1,5-di (4-hydroxyphenylthio) -3-oxapentane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,4- Bis [α-methyl-α- (4′-hydroxyphenyl) ethyl] benzene, 1,3-bis [α-methyl-α- 4'-hydroxyphenyl) ethyl] benzene, 4,4'-dihydroxydiphenyl sulfide, di (4-hydroxy-3-methylphenyl) sulfine, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'- Isopropoxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxyphenyl-4'-benzyloxyphenylsulfone, 4 -Hydroxy-3 ', 4'-tetramethylenebiphenylsulfone, 3,4-dihydroxyphenyl-p-tolylsulfone, 4,4'-dihydroxybenzophenone, benzyl 4-hydroxybenzoate, N, N'-di-m- Chlorophenylthiourea, Phenolic compounds such as N- (phenoxyethyl) -4-hydroxyphenylsulfonamide, zinc 4- [3- (p-tolylsulfonyl) propyloxy] salicylate, 4- [2- (p-methoxyphenoxy) ethyloxy] salicylic acid Zinc, zinc salts of aromatic carboxylic acids such as zinc 5- [p- (2-p-methoxyphenoxyethoxy) cumyl] salicylate, zinc p-chlorobenzoate, and organic acidic substances such as antipyrine complexes of zinc thiocyanate Etc. are exemplified.

  Specific examples of color formers (electron-donating dye precursors) that can be used in the heat-sensitive lithographic printing plate of the present invention include (1) 3,3′-bis (p-dimethylaminophenyl) as a triarylmethane compound. -6-dimethylaminophthalide (crystal violet lactone), 3,3'-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3- (1,2-dimethylindole- 3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-phenylindole-3- Yl) phthalide, 3,3-bis- (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindo) Ru-3-yl) -6-dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -5-dimethylaminophthalide, 3,3-bis (2-phenylindole-3- Yl) -5-dimethylaminophthalide, 3-p-dimethylaminophenyl-3- (1-methylpyrrol-2-yl) -6-dimethyl-aminophthalide, etc .: (2) 4,4 ′ as diphenylmethane compounds -Bis-dimethylaminobenzhydrin benzyl ether, N-halophenyl leucooramine, N-2,4,5-trichlorophenyl leucooramine, etc .: (3) Rhodamine B-anilinolactam, rhodamine as xanthene compounds Bp-nitroanilinolactam, rhodamine Bp-chloroanilinolactam, 3-diethylamino-7-di Benzylaminofluorane, 3-diethylamino-7-octylaminofluorane, 3-diethylamino-7-phenylfluorane, 3-diethylamino-7- (3,4-dichloroanilino) fluorane, 3-diethylamino-7- (2-chloroanilino) fluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilino Fluorane, 3-ethyl-tolylamino-6-methyl-7-anilinofluorane, 3-ethyl-tolylamino-6-methyl-7-phenethylfluorane, 3-diethylamino-7- (4-nitroanilino) fluorane, etc. (4) As thiazine compounds, benzoylleucomethylene blue, p-nitroben Zoyl leucomethylene blue and the like: (5) As spiro compounds, 3-methyl-spiro-dinaphthopyrans, 3-ethyl-spiro-dinaphthopyrans, 3,3'-dichloro-spiro-dinaphthopyrans, 3-benzyl-spiro-dinaphthopyrans, 3- Examples include methylnaphtho- (3-methoxy-benzo) -spiropyran, 3-propyl-spiro-dibenzopyran, and the like. Two or more of these may be used in combination.

  When the heat-sensitive lithographic printing plate of the present invention is a direct heat-sensitive lithographic printing plate, the image forming layer is preferably the outermost layer, and is a layer that becomes an image forming layer in printing. In general, when heat drawing is performed from a thermal head or the like, the hot-melt material and thermoplastic particles contained in the image forming layer melt at a certain temperature or higher. This melt is fixed to the thermal head to form a head residue, which sticks to the printing plate and causes sticking to cause white streaks in the image or increase the printing sound. However, in the present invention, as described above, the image forming layer of the direct heat-sensitive lithographic printing plate contains the compounds represented by the general formulas (1) to (4), so that a clear printed image can be obtained and sufficient. In addition to the effect of having excellent printing durability and reducing background stains, an excellent effect of further improving the sticking phenomenon can be obtained.

  Conventionally, thermal recording paper, etc. is generally bonded to the thermal head by adsorbing these hot melts with inorganic oils with high oil absorption such as silicon dioxide, zinc oxide, titanium dioxide, aluminum hydroxide, calcium carbonate. To prevent sticking phenomenon and prevent image drawing problems. However, when the image forming layer of the heat-sensitive lithographic printing plate contains the above inorganic pigment, the printing durability tends to be lowered. Therefore, in the present invention, the image forming layer preferably contains substantially no inorganic pigment. Here, “substantially” means that the amount of the inorganic pigment is less than 10% by mass relative to the total solid content of the image forming layer, and more preferably less than 5% by mass.

  The image-forming layer of the heat-sensitive lithographic printing plate of the present invention preferably has a dry film thickness of 0.5 to 20 μm from the viewpoints of printing durability of image areas, water resistance of non-image areas and mechanical strength. Furthermore, it is more preferable that it is 1-10 micrometers.

  As the water-resistant support that the heat-sensitive lithographic printing plate of the present invention has, a plastic film, resin-coated paper, water-resistant paper and the like can be used. Specifically, plastic films such as polyolefins such as polyethylene and polypropylene, polyethersulfone, polyester, poly (meth) acrylate, polycarbonate, polyamide, and polyvinyl chloride, and resin-coated paper with these plastics laminated or coated on the surface, melamine Paper that has been water-resistant by a wet paper strength agent such as formaldehyde resin, urea formaldehyde resin, or epoxidized polyamide resin can be used.

  The thickness of the support is preferably about 100 to 300 μm from the viewpoint of the recording suitability of the thermosensitive plate making apparatus and the lithographic printing press suitability.

  The surface of such a water-resistant support may be subjected to treatments such as plasma treatment, corona discharge treatment, deep ultraviolet irradiation treatment, and subbing treatment in order to enhance adhesion with the image forming layer. The undercoat layer provided on the water-resistant support by subbing treatment is an acetal resin such as polyvinyl butyral, a polyester resin having a hydroxyl group at the molecular chain end, a (meth) acrylic acid (meth) acrylic acid ester copolymer, A resin selected from vinylidene chloride / vinyl chloride copolymer and the like can be contained. The thickness of the undercoat layer is usually about 0.1 to 10 μm in dry film thickness.

  The heat-sensitive lithographic printing plate of the present invention is produced by coating and drying a coating solution prepared by mixing each material of the image forming layer and dissolving or dispersing in an appropriate solvent on a support by a known coating method. be able to. A preferred solvent is water. However, in order to prevent the image forming layer (and the intermediate layer) from being thermally denatured by heat during drying, the drying treatment is preferably performed in an atmosphere of 50 ° C. or lower for about 30 seconds to 10 minutes.

  The heat-sensitive lithographic printing plate of the present invention may be provided with an undercoat layer for improving the adhesion between the image forming layer and the support as described above, and may be conductive and antistatic as required. It is possible to provide a plurality of anti-curling layers for preventing the curling of a printing plate, a curling promoting layer for imparting a desired curling, and the like.

  Next, a plate making method using the above-described heat-sensitive lithographic printing plate of the present invention will be described. Since the heat-sensitive lithographic printing plate of the present invention has a heat-sensitive image-forming layer, an image is formed by irradiating light containing infrared light of, for example, 760 nm to 1200 nm by blending a photothermal conversion substance in the image-forming layer. The image portion can be formed by a solid-state laser and a semiconductor laser emitting infrared rays. In particular, laser exposure enables desired image-like recording directly from digital information of a computer. It is also possible to draw an image forming layer directly by heat with a thermal head or a heat block to form an image portion. However, the thermal head enables recording of a desired image directly from digital information of a computer. .

When a thermal head is used, a line printer using a thick film or thin film line head, a serial printer using a thin film serial head, or the like can be used. The recording energy density is preferably 10 to 100 mJ / mm ² , and the head image recording density is preferably 300 dpi or more in order to obtain a relatively high quality output image.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following examples, “parts” and “%” are based on mass unless otherwise indicated.

  As a compound of the general formula (1), 1,2-bis (3-methylphenoxy) ethane (KS-232 manufactured by Sanko Co., Ltd.) and a developer; 4-hydroxy-4'-isopropoxydiphenyl sulfone (Nippon Soda ( D-8), color former; 3-dibutylamino-6-methyl-7-anilinofluorane (ODB2 manufactured by Yamamoto Kasei Co., Ltd.) was previously individually zirconia beads in a small dynomill (bead mill). Using these, fine dispersion treatment was performed at a solid content concentration of 30% to prepare dispersion 1, dispersion 2, and dispersion 3, respectively. The dispersion particle diameter (median diameter) of Dispersion 1 was 0.52 μm as measured using LA920 manufactured by Horiba, Ltd. Next, an image forming layer coating solution was prepared according to the following formulation.

[Image forming layer coating solution]
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
Compound of general formula (1): Dispersion 1 (30% dispersion) 30 parts Developer: Dispersion 2 (30% dispersion) 30 parts Color developing agent: Dispersion 3 (30% dispersion) 9 Part / curing agent: 1.2 parts divinyl sulfone

After the corona discharge processing of double-sided polyethylene-coated paper having a thickness of 180 μm, the image forming layer coating liquid having the above-mentioned formulation is applied, and the image forming layer having a dry film thickness of 5 μm is provided to produce the direct heat-sensitive lithographic printing plate of the present invention. Obtained. The direct thermal printer (Toshiba Tec Corporation Barcode Printer B-433 Line Thermal Head 300 dpi) test printing mode (printing speed 2 inches / second, applied energy 18. Images were recorded at 6 mJ / mm ² ). Next, this printing plate is offset printing machine (HAMADA H234C: Hamada printing machine), ink; New Champion F-Gloss ink N: Dainippon Ink & Chemicals, Inc., dampening liquid; SLM-OD30: Mitsubishi Paper Industries 3 Printing was performed using a% diluted solution, and the presence or absence of sticking and the printing performance were evaluated.

Sticking was determined by the presence or absence of white streaks that occurred in a direction perpendicular to the printing direction in the solid black portion of the printed material. The evaluation of printing performance was carried out by evaluating the following three items: (1) image sharpness, (2) print ground stain, and (3) printing durability.
(1) Sharpness of image Judgment is based on the darkness of the printed image (10-point character) and the sharpness of the outline on the 20th sheet after printing is started.
○ ··· High character density and clear outline △ ···· High character density but poor outline × ···· Low character density and poor outline (2) Print stains Judgment is based on how dirty the background is.
○ ・ ・ ・ ・ No dirt △ ・ ・ ・ ・ Slightly spotted fine spots (commercial printable level)
× ··· Stains on the entire surface (impossible commercial printing)
(3) Number of printed sheets The approximate number of sheets until ink imperfection appears in the image area of the printed material is determined in units of 100 sheets.
The evaluation results are shown in Table 1.

  The 1,2-bis (3-methylphenoxy) ethane of Example 1 was changed to 1,2-diphenoxyethane (KS-235 manufactured by Sanko Co., Ltd.), and the water-soluble polymer compound was changed from gelatin to silanol-modified polyvinyl. It changed to alcohol (R1130 made from Kuraray Co., Ltd.), the water-proofing agent was changed to glyoxal, and the image formation layer coating liquid which consists of the following prescription was prepared. 1,2-diphenoxyethane was pre-dispersed in a small dynomill (bead mill) using zirconia beads at a solid concentration of 30% to prepare dispersion 4. The dispersion particle diameter (median diameter) of Dispersion 4 was 0.68 μm as measured using LA920 manufactured by Horiba, Ltd.

[Image forming layer coating solution]
Water-soluble polymer compound: Silanol group-modified PVA (10% aqueous solution) 100 parts (Kuraray R polymer R1130)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
Compound of general formula (1): Dispersion 4 (30% dispersion) 30 parts Developer: Dispersion 2 (30% dispersion) 30 parts Color developing agent: Dispersion 3 (30% dispersion) 9 Part / curing agent: 0.8 part of Glyoxal

  In the same manner as in Example 1, the image forming layer coating solution according to the above formulation was applied to a double-sided polyethylene-coated paper having a thickness of 180 μm, and an image forming layer having a dry film thickness of 5 μm was provided. Obtained. The direct thermal lithographic printing plate produced in this manner was recorded with an direct thermal printer and then printed with an offset printer in the same manner as in Example 1, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

  Carbon black was added as a photothermal conversion agent to the image forming layer coating solution of Example 2 to prepare an image forming layer coating solution as described below.

[Image forming layer coating solution]
Water-soluble polymer compound: Silanol group-modified PVA (10% aqueous solution) 100 parts (Kuraray R polymer R1130)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
Compound of general formula (1): Dispersion 4 (30% dispersion) 30 parts Developer: Dispersion 2 (30% dispersion) 30 parts Color developing agent: Dispersion 3 (30% dispersion) 9 Parts / photothermal conversion agent: carbon black as solids 5 parts (Dainippon Ink Chemical Co., Ltd. SD9020)
・ Curing agent: Glyoxal 0.8 parts (Nippon Synthetic Chemical Co., Ltd.)

  A polyester film having a thickness of 100 μm was subjected to corona discharge processing, and then a coating liquid having the above formulation was applied to provide an image forming layer having a dry film thickness of 5 μm to obtain a heat-sensitive lithographic printing plate of the present invention. The thus produced heat-sensitive lithographic printing plate was subjected to image exposure with a semiconductor laser (wavelength 830 nm, output 500 mw). The resolution was 2400 dpi in both the scanning direction and the sub-scanning direction. After the image exposure, printing was performed with an offset printer in the same manner as in Example 1 to evaluate the printing performance. The results are shown in Table 1.

  The following image forming layer coating solution was prepared in the same manner as in Example 1 except that silicon dioxide was added to Example 1 at 5.3% of the total solid content.

[Image forming layer coating solution]
Inorganic pigment; silicon dioxide 2.5 parts (Tosoh Silica Co., Ltd. AY-601)
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
Compound of general formula (1): Dispersion 1 (30% dispersion) 30 parts Developer: Dispersion 2 (30% dispersion) 30 parts Color developing agent: Dispersion 3 (30% dispersion) 9 Part / curing agent: 1.2 parts divinyl sulfone

  In the same manner as in Example 1, the image forming layer coating solution according to the above formulation was applied to a double-sided polyethylene-coated paper having a thickness of 180 μm, and an image forming layer having a dry film thickness of 5 μm was provided to produce the direct heat-sensitive lithographic printing plate of the present invention. Obtained. In the same manner as in Example 1, after recording an image on the direct thermal lithographic printing plate thus produced with a direct thermal printer, printing was performed with an offset printer, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

  The following image forming layer was prepared in the same manner as in Example 1 except that silicon dioxide was added to Example 1 at 10.2% of the total solid content.

[Image forming layer coating solution]
Inorganic pigment: 5.1 parts of silicon dioxide (Tosoh Silica Co., Ltd. AY-601)
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
Compound of general formula (1): Dispersion 1 (30% dispersion) 30 parts Developer: Dispersion 2 (30% dispersion) 30 parts Color developing agent: Dispersion 3 (30% dispersion) 9 Part / curing agent: 1.2 parts divinyl sulfone

  In the same manner as in Example 1, the image forming layer coating solution according to the above formulation was applied to a double-sided polyethylene-coated paper having a thickness of 180 μm, and an image forming layer having a dry film thickness of 5 μm was provided to produce the direct heat-sensitive lithographic printing plate of the present invention. Obtained. In the same manner as in Example 1, an image was recorded on the direct thermal lithographic printing plate produced in this manner with a direct thermal printer, and then the presence or absence of sticking and the printing performance were evaluated with an offset printing machine. The results are shown in Table 1.

  As a compound of the general formula (2), 2-benzyloxynaphthalene (BON manufactured by Yamada Chemical Co., Ltd.) was finely dispersed in advance with a small dynomill in the same manner as in Example 1 to prepare dispersion 5. (Dispersion particle size 0.82 μm) An image forming layer coating solution was prepared in the same manner as in Example 1 except that Dispersion 5 was used instead of Dispersion 1 in Example 1, and applied to double-sided polyethylene-coated paper. The direct heat-sensitive lithographic printing plate of the present invention was obtained. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and the presence or absence of sticking were evaluated. The results are shown in Table 1.

  As a compound of the general formula (2), 2-p-chlorobenzyloxynaphthalene (reagent) was finely dispersed in advance with a small dynomill in the same manner as in Example 2 to prepare dispersion 6 (dispersed particle size of 1.25 μm). ). An image-forming layer coating solution was prepared in the same manner as in Example 2 except that the dispersion 6 was used in place of the dispersion 4 in Example 2, coated on double-sided polyethylene-coated paper, and the direct heat-sensitive lithographic plate of the present invention. A printed version was obtained. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and the presence or absence of sticking were evaluated. The results are shown in Table 1.

  An image-forming layer coating solution was prepared in the same manner as in Example 3 except that the dispersion 6 was used instead of the dispersion 4 in Example 3. The polyester film was coated in the same manner as in Example 3 to obtain a heat-sensitive lithographic printing plate of the present invention. In the same manner as in Example 3, image exposure was performed with a semiconductor laser, printing was performed with an offset printer, and printing performance was evaluated. The evaluation results are shown in Table 1.

  An image forming layer coating solution was prepared in the same manner as in Example 4 except that the dispersion 5 was used in place of the dispersion 1 in Example 4. In the same manner as in Example 4, it was coated on a double-sided polyethylene-coated paper to obtain a direct heat-sensitive lithographic printing plate of the present invention. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and the presence or absence of sticking were evaluated. The results are shown in Table 1.

  An image forming layer coating solution was prepared in the same manner as in Example 5 except that the dispersion 5 was used in place of the dispersion 1 in Example 5. In the same manner as in Example 5, it was coated on double-sided polyethylene-coated paper to obtain a direct heat-sensitive lithographic printing plate of the present invention. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and the presence or absence of sticking were evaluated. The results are shown in Table 1.

  As a compound of the general formula (3), di (p-methylbenzyl) oxalate (HS3520 manufactured by Dainippon Ink & Chemicals, Inc.) was finely dispersed in advance with a small dynomill in the same manner as in Example 1 to obtain dispersion 7 (Dispersed particle size 0.68 μm). An image-forming layer coating solution is prepared in the same manner as in Example 1 except that the dispersion 7 is used instead of the dispersion 1 in Example 1, coated on double-sided polyethylene-coated paper, and the direct heat-sensitive lithographic plate of the present invention. A printed version was obtained. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and sticking were evaluated. The results are shown in Table 1.

  As a compound of general formula (3), dibenzyl oxalate (HS2046 manufactured by Dainippon Ink & Chemicals, Inc.) was finely dispersed in advance with a small dynomill in the same manner as in Example 2 to prepare dispersion 8. (Dispersion particle size 0.52 μm) An image forming layer coating solution was prepared in the same manner as in Example 2 except that Dispersion 8 was used instead of Dispersion 4 in Example 2, and applied to double-sided polyethylene-coated paper. The direct heat-sensitive lithographic printing plate of the present invention was obtained. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and the presence or absence of sticking were evaluated. The results are shown in Table 1.

  An image forming layer coating solution was prepared in the same manner as in Example 3 except that the dispersion 8 was used instead of the dispersion 4 in Example 3. The polyester film was coated in the same manner as in Example 3 to obtain a heat-sensitive lithographic printing plate of the present invention. In the same manner as in Example 3, image exposure was performed with a semiconductor laser, printing was performed with an offset printer, and printing performance was evaluated. The evaluation results are shown in Table 1.

  An image forming layer coating solution was prepared in the same manner as in Example 4 except that the dispersion 7 was used in place of the dispersion 1 in Example 4. In the same manner as in Example 4, it was coated on a double-sided polyethylene-coated paper to obtain a direct heat-sensitive lithographic printing plate of the present invention. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and the presence or absence of sticking were evaluated. The results are shown in Table 1.

  An image forming layer coating solution was prepared in the same manner as in Example 5, except that the dispersion 7 was used instead of the dispersion 1 in Example 5. In the same manner as in Example 5, it was coated on double-sided polyethylene-coated paper to obtain a direct heat-sensitive lithographic printing plate of the present invention. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and the presence or absence of sticking were evaluated. The results are shown in Table 1.

  As a compound of the general formula (4), 1,2-diphenoxymethylbenzene (PMB-2 manufactured by Nikka Chemical Co., Ltd.) was finely dispersed in advance with a small dynomill in the same manner as in Example 1, and a dispersion 9 was obtained. It was produced (dispersed particle size 0.75 μm). An image-forming layer coating solution was prepared in the same manner as in Example 1 except that the dispersion 9 was used in place of the dispersion 1 in Example 1, coated on double-sided polyethylene-coated paper, and the direct heat-sensitive lithographic plate of the present invention. A printed version was obtained. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and the presence or absence of sticking were evaluated. The results are shown in Table 1.

  As a compound of the general formula (4), 1,4-di (2-methylphenoxymethyl) benzene (reagent) was finely dispersed in advance with a small dynomill in the same manner as in Example 2 to prepare dispersion 10 (dispersion) Particle size 0.97 μm). An image-forming layer coating solution was prepared in the same manner as in Example 2 except that the dispersion 10 was used in place of the dispersion 4 in Example 2, coated on double-sided polyethylene-coated paper, and the direct heat-sensitive lithographic plate of the present invention. A printed version was obtained. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and the presence or absence of sticking were evaluated. The results are shown in Table 1.

  An image forming layer coating solution was prepared in the same manner as in Example 3 except that the dispersion 10 was used instead of the dispersion 4 in Example 3. The polyester film was coated in the same manner as in Example 3 to obtain a heat-sensitive lithographic printing plate of the present invention. In the same manner as in Example 3, image exposure was performed with a semiconductor laser, printing was performed with an offset printer, and printing performance was evaluated. The evaluation results are shown in Table 1.

  An image forming layer coating solution was prepared in the same manner as in Example 4 except that the dispersion 9 was used in place of the dispersion 1 in Example 4. In the same manner as in Example 4, it was coated on a double-sided polyethylene-coated paper to obtain a direct heat-sensitive lithographic printing plate of the present invention. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and the presence or absence of sticking were evaluated. The results are shown in Table 1.

  An image forming layer coating solution was prepared in the same manner as in Example 5 except that the dispersion 9 was used in place of the dispersion 1 in Example 5. In the same manner as in Example 5, it was coated on double-sided polyethylene-coated paper to obtain a direct heat-sensitive lithographic printing plate of the present invention. Next, after recording an image with a direct thermal printer in the same manner as in Example 1, printing was performed with an offset printer, and printing performance and the presence or absence of sticking were evaluated. The results are shown in Table 1.

  The following image-forming layer coating solution was prepared in the same manner as in Example 1 except that stearic acid amide was added to Example 1 at a solid content ratio of 1,2-bis (3-methylphenoxy) ethane of Dispersion 1 of 20%. .

[Image forming layer coating solution]
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
Compound of general formula (1): Dispersion 1 (30% dispersion) 30 parts Stearate amide dispersion (nonvolatile content 25%) 7.2 parts (Chukyo Yushi Co., Ltd. High Micron L271)
・ Developer: 30 parts of dispersion 2 (30% dispersion) ・ Coloring agent: 9 parts of dispersion 3 (30% dispersion) ・ Curing agent: 1.2 parts of divinyl sulfone

  In the same manner as in Example 1, the image forming layer coating solution according to the above formulation was applied to a double-sided polyethylene-coated paper having a thickness of 180 μm, and an image forming layer having a dry film thickness of 5 μm was provided. Obtained. In the same manner as in Example 1, after recording an image on the direct thermal lithographic printing plate thus produced with a direct thermal printer, printing was performed with an offset printer, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

  Example 1 is the same as Example 1 except that the carboxy-modified styrene-butadiene copolymer (Rackstar 7132-C) in Example 1 is changed to a styrene-butadiene copolymer (Rackstar DS-206, manufactured by Dainippon Ink & Chemicals, Inc.). Similarly, the following image forming layer coating solution was prepared.

[Image forming layer coating solution]
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of styrene butadiene copolymer (solid content 49%) (Dainippon Ink Chemical Co., Ltd. Rack Star DS-206 Tg 25 ° C)
Compound of general formula (1): Dispersion 1 (30% dispersion) 30 parts Developer: Dispersion 2 (30% dispersion) 30 parts Color developing agent: Dispersion 3 (30% dispersion) 9 Part / curing agent: 1.2 parts divinyl sulfone

  In the same manner as in Example 1, the image forming layer coating solution according to the above formulation was applied to a double-sided polyethylene-coated paper having a thickness of 180 μm, and an image forming layer having a dry film thickness of 5 μm was provided to produce the direct heat-sensitive lithographic printing plate of the present invention. Obtained. In the same manner as in Example 1, after recording an image on the direct thermal lithographic printing plate thus produced with a direct thermal printer, printing was performed with an offset printer, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

  The following image formation was performed in the same manner as in Example 1 except that the carboxy-modified styrene-butadiene copolymer (Luckster 7132-C) in Example 1 was changed to a carbonyl-modified styrene-butadiene copolymer (Nipol LX407BP manufactured by Nippon Zeon Co., Ltd.). A layer coating solution was prepared.

[Image forming layer coating solution]
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin; styrene butadiene copolymer (solid content 50%) 30 parts (Nippon ZEON Corporation Nipol LX407BP Tg 80 ° C)
Compound of general formula (1): Dispersion 1 (30% dispersion) 30 parts Developer: Dispersion 2 (30% dispersion) 30 parts Color developing agent: Dispersion 3 (30% dispersion) 9 Part / curing agent: 1.2 parts divinyl sulfone

  In the same manner as in Example 1, the image forming layer coating solution according to the above formulation was applied to a double-sided polyethylene-coated paper having a thickness of 180 μm, and an image forming layer having a dry film thickness of 5 μm was provided. Obtained. In the same manner as in Example 1, after recording an image on the direct thermal lithographic printing plate thus produced with a direct thermal printer, printing was performed with an offset printer, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

<Comparative example 1>
The same as Example 1 except that the dispersion liquid 1 containing 1,2-bis (3-methylphenoxy) ethane, which is a compound of the general formula (1), was removed from the image forming layer coating liquid used in Example 1. The following image forming layer coating solution was prepared.

[Image forming layer coating solution]
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
・ Developer: 30 parts of dispersion 2 (30% dispersion) ・ Coloring agent: 9 parts of dispersion 3 (30% dispersion) ・ Curing agent: 1.2 parts of divinyl sulfone

  A double-sided polyethylene-coated paper having a thickness of 180 μm is subjected to corona discharge processing, and then an image-forming layer coating solution having the above-mentioned formulation is applied to obtain an image-forming layer having a dry film thickness of 5 μm. Got a version. In the same manner as in Example 1, after recording an image on the direct thermal lithographic printing plate thus produced with a direct thermal printer, printing was performed with an offset printing machine, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

<Comparative example 2>
The dispersion 1 containing 1,2-bis (3-methylphenoxy) ethane, which is a compound of the general formula (1), was removed from the image forming layer coating solution used in Example 1, and then silicon dioxide was added to the total solids. The following image forming layer coating solution was prepared in the same manner as in Example 1 except that it was added so that the fraction was 28.0%.

[Image forming layer coating solution]
Inorganic pigment: 14 parts of silicon dioxide (Tosoh Silica Co., Ltd. AY-601)
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
・ Developer: 30 parts of dispersion 2 (30% dispersion) ・ Coloring agent: 9 parts of dispersion 3 (30% dispersion) ・ Curing agent: 1.2 parts of divinyl sulfone

  A double-sided polyethylene-coated paper having a thickness of 180 μm is subjected to corona discharge processing, and then an image-forming layer coating liquid having the above-mentioned formulation is applied to obtain an image-forming layer having a dry film thickness of 5 μm. Got a version. In the same manner as in Example 1, after recording an image on the direct thermal lithographic printing plate thus produced with a direct thermal printer, printing was performed with an offset printing machine, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

<Comparative Example 3>
Paraffin wax dispersion (Chukyo Yushi Co., Ltd. Hydrin L703, melting point) instead of dispersion 1 containing 1,2-bis (3-methylphenoxy) ethane which is the compound of general formula (1) used in Example 1 The following image forming layer coating solution was prepared in the same manner as in Example 1 except that an equal amount of 75 ° C.) was used.

[Image forming layer coating solution]
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
-Paraffin wax dispersion (non-volatile content 35%) 26 parts (Chukyo Yushi Co., Ltd. Hydrin L703)
・ Developer: 30 parts of dispersion 2 (30% dispersion) ・ Coloring agent: 9 parts of dispersion 3 (30% dispersion) ・ Curing agent: 1.2 parts of divinyl sulfone

  A double-sided polyethylene-coated paper having a thickness of 180 μm is subjected to corona discharge machining, and then an image-forming layer coating solution having the above-mentioned formulation is applied to obtain an image-forming layer having a dry film thickness of 5 μm. Got a version. In the same manner as in Example 1, after recording an image on the direct thermal lithographic printing plate thus produced with a direct thermal printer, printing was performed with an offset printing machine, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

<Comparative example 4>
Instead of dispersion 1 containing 1,2-bis (3-methylphenoxy) ethane, which is the compound of general formula (1) used in Example 1, carnauba wax dispersion (Chukyo Oil & Fats Co., Ltd. Cellosol 524, melting point) The following image forming layer coating solution was prepared in the same manner as in Example 1 except that an equal amount of 83 ° C.) was used.

[Image forming layer coating solution]
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
-Carnauba wax dispersion (non-volatile content 30%) 30 parts (Chukyo Oil & Fats Co., Ltd. Cellosol 524)
・ Developer: 30 parts of dispersion 2 (30% dispersion) ・ Coloring agent: 9 parts of dispersion 3 (30% dispersion) ・ Curing agent: 1.2 parts of divinyl sulfone

  A double-sided polyethylene-coated paper having a thickness of 180 μm is subjected to corona discharge processing, and then an image-forming layer coating solution having the above-mentioned formulation is applied to obtain an image-forming layer having a dry film thickness of 5 μm. Got a version. In the same manner as in Example 1, after recording an image on the direct thermal lithographic printing plate thus produced with a direct thermal printer, printing was performed with an offset printing machine, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

<Comparative Example 5>
Instead of the dispersion 1 containing 1,2-bis (3-methylphenoxy) ethane, which is the compound of the general formula (1) used in Example 1, a montanic acid ester wax dispersion (Chukyo Yushi Co., Ltd. Hydrin J537) The following image-forming layer coating solution was prepared in the same manner as in Example 1 except that an equal amount of a melting point of 83 ° C. was used.

[Image forming layer coating solution]
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
・ Montanic acid ester wax dispersion (non-volatile content 30%) 30 parts (Chukyo Yushi Co., Ltd. Hydrin J537)
・ Developer: 30 parts of dispersion 2 (30% dispersion) ・ Coloring agent: 9 parts of dispersion 3 (30% dispersion) ・ Curing agent: 1.2 parts of divinyl sulfone

  A double-sided polyethylene-coated paper having a thickness of 180 μm is subjected to corona discharge processing, and then an image-forming layer coating solution having the above-mentioned formulation is applied to obtain an image-forming layer having a dry film thickness of 5 μm. Got a version. In the same manner as in Example 1, after recording an image on the direct thermal lithographic printing plate thus produced with a direct thermal printer, printing was performed with an offset printing machine, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

<Comparative Example 6>
Instead of the dispersion 1 containing 1,2-bis (3-methylphenoxy) ethane, which is the compound of the general formula (1) used in Example 1, a dispersion of stearamide (Chukyo Yushi Co., Ltd. Hymicron) The following image forming layer coating solution was prepared in the same manner as in Example 1 except that an equal amount of L271, melting point 100 ° C.) was used.

[Image forming layer coating solution]
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
・ 36 parts of stearamide dispersion (non-volatile content 25%) (Chukyo Yushi Co., Ltd. High Micron L271)
・ Developer: 30 parts of dispersion 2 (30% dispersion) ・ Coloring agent: 9 parts of dispersion 3 (30% dispersion) ・ Curing agent: 1.2 parts of divinyl sulfone

  A double-sided polyethylene-coated paper having a thickness of 180 μm is subjected to corona discharge processing, and then an image-forming layer coating liquid having the above-mentioned formulation is applied to obtain an image-forming layer having a dry film thickness of 5 μm. Got a version. In the same manner as in Example 1, after recording an image on the direct thermal lithographic printing plate thus produced with a direct thermal printer, printing was performed with an offset printing machine, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

<Comparative Example 7>
Instead of the dispersion 1 containing 1,2-bis (3-methylphenoxy) ethane, which is the compound of the general formula (1) used in Example 1, a zinc stearate dispersion (Chukyo Yushi Co., Ltd. Hydrin Z7, The following image forming layer coating solution was prepared in the same manner as in Example 1 except that an equal amount of a melting point of 120 ° C. was used.

[Image forming layer coating solution]
Water-soluble polymer compound: gelatin (12% aqueous solution) 80 parts (Nippi IK3000)
-Thermoplastic resin: 30 parts of carboxy-modified styrene-butadiene copolymer (solid content 45%) (Dainippon Ink Chemical Co., Ltd., Luck Star 7132-C Tg 60 ° C)
・ Zinc stearate dispersion (non-volatile content 31%) 29 parts (Chukyo Yushi Co., Ltd. Hydrin Z7)
・ Developer: 30 parts of dispersion 2 (30% dispersion) ・ Coloring agent: 9 parts of dispersion 3 (30% dispersion) ・ Curing agent: 1.2 parts of divinyl sulfone

  A double-sided polyethylene-coated paper having a thickness of 180 μm is subjected to corona discharge processing, and then an image-forming layer coating solution having the above-mentioned formulation is applied to obtain an image-forming layer having a dry film thickness of 5 μm. Got a version. In the same manner as in Example 1, after recording an image on the direct thermal lithographic printing plate thus produced with a direct thermal printer, printing was performed with an offset printing machine, and the presence or absence of sticking and the printing performance were evaluated. The results are shown in Table 1.

  As can be seen from the results shown in Table 1, the image-forming layer contains the compounds represented by the general formulas (1) to (4) so that the printed image is clear, has little background stains, and has excellent printing durability. A lithographic printing plate can be obtained. Further, it is possible to obtain a direct heat-sensitive lithographic printing plate in which sticking, which has been a problem with direct heat-sensitive lithographic printing plates, is reduced, and the lipophilicity of the image area and the hydrophilicity of the non-image area are balanced. Further, as is clear from the description of the above examples, the heat-sensitive lithographic printing plate of the present invention can be drawn without using a thermal head or an infrared laser and thereafter developed.

Claims (4)

In a heat-sensitive lithographic printing plate having an image-forming layer containing a thermoplastic resin and a water-soluble polymer compound on a water-resistant support, the image-forming layer is composed of compounds represented by the following general formulas (1) to (4) A heat-sensitive lithographic printing plate comprising at least one selected from the above.

(In the formula, X ₁ represents —O— or —CO—O—, and R _{1 to} R ₆ represent a hydrogen atom, an alkyl group, and an aryl group, respectively, and n represents an integer from 1 to 10.)

(In the formula, R ₇ represents an alkyl group, an aryl group, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, or an arylsulfonyl group.)

(Wherein R ₈ and R ₉ represent a hydrogen atom, a halogen atom, an alkyl group having 4 or less carbon atoms, or an alkoxy group. X ₂ represents a simple bond or —O—, and n represents an integer of 1 to 4. Show.)

(Wherein R ₁₀ , R _{10 ′} , R ₁₁ and R _{11 ′} represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group or an aryloxy group. .)   2. The heat-sensitive lithographic printing plate according to claim 1, wherein the image forming layer contains substantially no inorganic pigment.   The heat-sensitive lithographic printing plate according to claim 1, wherein the thermoplastic resin is a self-crosslinking type synthetic rubber latex.   The heat-sensitive lithographic printing plate according to any one of claims 1 to 3, wherein the heat-sensitive lithographic printing plate is a direct heat-sensitive lithographic printing plate.